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Biology 1229 Extinction
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“the cessation of existence of a species”
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IUCN categories Extinct No reasonable doubt that the taxon is gone. 717 animal and 87 plant species since 1500
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Lytta mirifica huia Labrador duck Stead’s Bush Wren Great Auk Thylacine Steller’s Sea Cow Passenger Pigeon dodo Quagga
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IUCN categories Extinct in the wild Species only exists in captivity or cultivation 37 animals and 28 plants
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Extinct in the wild St Helena Redwood Wood’s Cycad Hawaiian Crow Redtail Shark Black-footed ferret Partula snails
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IUCN categories Critically endangered Extremely high risk of extinction in the wild 3240 species (up from 3124 in 2007 and 3071 in 2006) Includes 6 species of fungi
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Baiji North American Burying beetle Southern Bluefin Tuna Black Rhino Kakapo
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IUCN categories Endangered Very high risk of extinction in the wild 4768 species
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IUCN categories Vulnerable High risk of extinction in the wild 8911 species
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IUCN categories Near Threatened Ongoing conservation measures required to prevent risk of extinction 3513 Least concern Widespread, abundant & safe 17675 Data deficient No assessment possible 5561
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Gaps in knowledge Almost all invertebrates Apart from ‘showy’ ones Collected beetles Butterflies Dragonflies Poor knowledge of tropics, esp. in Africa The vast majority of described species are known from only a few specimens
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A Global Extinction Crisis >33% of frogs threatened ¼ of Mammals face extinction 15-37% of species extinct by 2050 70% of Butterfly species in decline
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Why should we care? The sadness of losing biodiversity Our moral responsibilities Ecosystem services
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Ecosystem services All the free stuff we get from nature Water purification, decomposition, dung removal, pollination, O2 repletion, CO2 absorption, food, pharmaceutical products etc. $16-54 Trillion (i.e. $16 000 000 000 000) per year… in 1997!
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Why do species go extinct I? Natural extinctions Population changes Natural disasters Evolution, migration and habitat change
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Why do species go extinct II? Anthropogenic influence
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Habitat destruction Invasive species Overkill Climate Change
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The four horsemen of the extinction crisis I: Habitat destruction
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The four horsemen of the extinction crisis II: Overkill
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The four horsemen of the extinction crisis III: Invasive species Stoat (NZ) House Mouse (Many places!) Red Fox (Australia) Brush-tailed possum (NZ) Rhododendron (Scotland) Emerald Ash Borer (SW ON) NZ Flatworm (Ireland) Zebra Mussel (Great Lakes) European Starling (Many places!)
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The four horsemen of the extinction crisis IV: Climate change
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